Field of the Invention
An improved two-piece flashing for roof top vent pipes, characterized by a hard plastic frustroconical base member and a sealing collar of softer, elastomeric material. The invention resides in the manner of joining the elastomeric sealing collar to a ring mount assembly on the frustroconical base member.
Brief Description of the Prior Art
Various prior art flashings are known wherein a flexible sealing collar permits various angles and sizes of vent pipes to be sealed against moisture, for range of roof pitch slope angles. For example, applicant's prior patent, HASTY, (U.S. Pat. No. 4,563,847) illustrates an improved universal flashing characterized by a one-piece elastomeric material wherein larger vent pipe diameters can be accomplished simply by separating one or more projections from a sealing ring collar. The exact type of elastomeric sealing collar used in the present invention is not critical. The critical aspect of the invention is the manner in which the elastomeric sealing collar has a proximate end that engages against a hard plastic ring mount assembly on the frustroconical member.
Examples of pertinent prior art, two-piece collar and hard base flashings are LOGSDON (U.S. Pat. No. 4,265,058) and KIFER (U.S. Pat. No. 4,526,407). LOGSDON '058 alleges criticality in an upwardly open channel, a plurality of sealing flanges that extend circularly around the wall to project radially inward, together with an annular skirt that must be molded downwardly into that channel. KIFER '407 critically requires a closed-loop type of overmolding technique, and specifically alleges a more water-tight seal between the collar and the hard base, than realizable with an upwardly open channel design, such as taught by LOGSDON '058. The term "overmolding" herein is used in its conventional sense, to describe molding of a collar directly upon a flange of a base member by injecting an elastomeric collar material into a mold cavity that is clamped or otherwise surrounding the flange, so that the overmolded collar material will fuse to the flange to make an interconnection.
Other pertinent examples of known ways to engage the top and bottom of a horizontal flange are the earlier patents to FIFE (U.S. Pat. No. 1,258,884), BUCKLES et al. (U.S. Pat. No. 1,615,929), DIBLEY (U.S. Pat. No. 3,098,663), and KIFER (U.S. Pat. No. 3,313,559). Each of these patents illustrate simpler techniques for molding or otherwise mounting a soft, elastomeric collar into a harder material base, and in each approach a channel-type interconnect or a simple overmolding is employed.
The present invention is characterized by a single-size hard base, with elastomeric collars which may be universal, or individually sized to accommodate three-inch, two-inch and 1.5 inch vent pipes, for example. The present invention combines structural improvements to a ring mount assembly with overmolding, so that a greater resistance to bending moments and the possibility of water entry is achieved. Applicant's mounting categorically involves a ring mount assembly having a generally planar upper surface, a first downward leg relatively inward on a ring mount assembly, and a second downward leg, relatively outward on the ring mount assembly. The ring mount assembly preferably further comprises eight oval slots, and eight C-shaped slots, spaced circumferentially on either side of the second downward leg.
As such, the present invention is distinguished from prior art approaches by an elastomeric collar which has greater resistance to bending moments, so that the forces applied to the distal end of the collar, (from a contact with a vent pipe), will not bend the entire proximate end of the elastomeric collar around the ring mount assembly. The present invention permits both a certain amount of flexibility, and a point of rotation that is generally about the diameter of the second downward leg, so that a sealing between the base and the collar radially outward therefrom will not be destroyed.